Abstract: OBJECTIVE To investigate the compatibility of APIs with nifedipine sustained release tablets and to provide basis and information for better prescription design, control and quality improvement. METHODS According to the determination methods for the relative substances in nifedipine in ChP2015, to examine the changes of relative substances, as effects of different excipients on the photostability of nifedipine sustained-release tablets. RESULTS In the light conditions, nifedipine could produce photodegradation impurities 2, and microcrystalline cellulose and magnesium stearate will accelerate the production of impurities 2. CONCLUSION Under the conditions required to meet the requirements of the relevant preparation, it is recommended to use as little or no microcrystalline cellulose and magnesium stearate.